I feel like the quotidian definition of war would be something like 'state induced violence to coerce results' and so, no, a policy that is specifically not violent and indeed is being done instead of violence would be definitely not-war. I suppose you can stretch the definition to include it. But if 'anything that kills people' is war, then like, not having universal Healthcare is war, as is understaffing emergency rooms... So that is clearly not a useful definition of war.
Sanctions are akin to siege warfare. You don't have to fire a shot, the threat is enough, and you starve the population until they can't handle their kids dying and they overthrow the leadership and surrender. That's literally what the desired outcome is with sanctions. It is absolutely violence and warfare by any definition.
Clausewitz said that war is a continuation of state policy by other means; in this view neither is the 'opposite' of the other because in both cases it's a government pursuing some political object. I suppose the real 'opposite of war' would be the absence of state policy. Apathetic indifference to whatever the other party is doing.
> 24. WAR IS A MERE CONTINUATION OF POLICY BY OTHER MEANS.
> We see, therefore, that War is not merely a political act, but also a real political instrument, a continuation of political commerce, a carrying out of the same by other means. All beyond this which is strictly peculiar to War relates merely to the peculiar nature of the means which it uses. That the tendencies and views of policy shall not be incompatible with these means, the Art of War in general and the Commander in each particular case may demand, and this claim is truly not a trifling one. But however powerfully this may react on political views in particular cases, still it must always be regarded as only a modification of them; for the political view is the object, War is the means, and the means must always include the object in our conception.
Obviously Clausewitz's assertions are controversial but I think it's a viewpoint worth mentioning since you invited a broad consideration of the matter.
1. https://moderndiplomacy.eu/2022/06/29/economic-sanctions-as-...